Bess, an orangutan at the Phoenix Zoo, keeps cool under a wet sheet and a hose, Friday, June 28, 2013 in Phoenix. Excessive heat warnings will continue for much of the Desert Southwest as building high pressure triggers major warming in eastern California, Nevada, and Arizona. Dangerously hot temperatures are expected across the Arizona deserts throughout the week with a high of 118 Friday. (AP Photo/Matt York)

Bess, an orangutan at the Phoenix Zoo, keeps cool under a wet sheet and a hose, Friday, June 28, 2013 in Phoenix. Excessive heat warnings will continue for much of the Desert Southwest as building high pressure triggers major warming in eastern California, Nevada, and Arizona. Dangerously hot temperatures are expected across the Arizona deserts throughout the week with a high of 118 Friday. (AP Photo/Matt York)